The primary purpose of this project is to test an environmental intervention aimed at improving nighttime sleep and decreasing daytime sleepiness among nursing home residents. The intervention will be targeted at improving disruptive environmental conditions that contribute to sleep disturbance. This 5-year project will be a randomized, controlled trial performed in 4 community nursing homes, with an expected enrollment of 120 subjects. Residents with both daytime sleepiness and nighttime sleep impairment will be targeted for the study. Subjects randomized to the treatment group will receive a daytime/nighttime (i.e., 24-hour) intervention that combines a previously-tested nighttime intervention (involving measures to decrease noise, light and sleep-disruptive nursing care practices) with a daytime intervention (involving structured sleep and awakening times, natural bright light exposure, increased physical activity, and limitation of time spent in bed). Control subjects will receive usual care. Outcome measures will include measures of sleep versus wakefulness (estimated by 24 hour wrist actigraphy) and behavior (measured by 24 hour behavioral observations). In addition, certain measures of the process of the intervention will be collected (i.e., noise levels, light exposure, in-bed time, and activity levels) to test the theoretical framework of the intervention. The major hypotheses are that the intervention will be associated with improvement in nighttime sleep and decreased daytime sleepiness and agitation. Results of this application may lead to dramatic changes in the nursing home environment, with the potential for significant improvement in the quality of life and well-being of this vulnerable population.